Eating mushrooms with any signs of mold is not recommended. White mold on mushrooms indicates they have spoiled and may contain toxins that can cause illness if consumed. However, in some cases white mold may be harmless, so determining if white-molded mushrooms are safe depends on the type of mushroom and mold.
Quick Answers
– Eating mushrooms with white mold is generally unsafe due to potential mold toxins.
– White mold on store-bought mushrooms means they should be discarded.
– With wild mushrooms, only eat them if you can identify the mushroom and mold species and know the mold is benign.
– Cooking does not make molded mushrooms safe to eat.
– Slicing away visible mold does not remove toxic mold roots penetrating the mushroom.
Should You Eat Store-Bought Mushrooms with White Mold?
White mold growth on store-bought mushrooms, such as white button, cremini, or portobello mushrooms, is an indication they have spoiled and should be discarded. These commercially grown mushrooms are considered food products, not foraged items, and have stricter safety standards regarding mold.
Mold growth on food in the refrigerator is a sign of spoilage. Refrigeration temperatures only slow mold growth, they do not prevent it. Once mold has established itself on refrigerated food, including mushrooms, it means the item is past safe eating quality and should be thrown out.
Eating moldy store-bought mushrooms can cause symptoms such as:
- Nausea, vomiting, and diarrhea
- Headaches and other flu-like symptoms
- Respiratory irritation or allergy symptoms in sensitive individuals
These effects are due to mycotoxins produced by the mold fungus. Mycotoxins are toxic chemical byproducts of the mold’s metabolism. Even a small amount of mold growth can indicate the presence of these mushroom toxins.
Appearance of White Mold on Store-Bought Mushrooms
White mold growth on store-bought mushrooms may appear as:
- White fuzzy spots or patches
- White filaments or threads on the mushroom cap or stem
- White powdery or crusty material on the surface
This white mold is often the fungus Ascomycota, a common food spoilage organism. Other molds like Mucor and Rhizopus can also grow on old or damaged mushrooms, causing a fuzzy white appearance.
Is it Safe to Cut Away the Moldy Spots?
It is not considered safe to simply cut away moldy portions of store-bought mushrooms and eat the rest. Mold filaments likely have spread into areas of the mushroom that appear unaffected. Research on store-bought produce has found mold can penetrate well past the visible mold site, leaving behind toxin-producing roots even in areas that look clean.
What About Wild Mushrooms with White Mold?
For wild mushrooms like chanterelles, morels, and porcini that are foraged, the criteria for mold safety depends on first identifying both the mushroom species and the mold species. With this information, it may be possible to determine if the mold poses a hazard or not.
Often, white mold on wild mushrooms is one of several common environmental mold fungi considered non-toxic. These can include Cladosporium, Mycotypha, Trichoderma, or Epicoccum species. Some of these molds may even have protective antioxidant properties if consumed.
However, if the white mold is identified as a known mycotoxin producer like Aspergillus flavus or Fusarium molds, then the mushroom should be avoided. Proper identification of wild mushroom and mold species requires considerable expertise.
When is White Mold on Wild Mushrooms Considered Safe?
Here are some instances when white mold growth on wild mushrooms is generally considered safe:
- When the mushroom can be accurately identified as non-toxic.
- When the white mold species can be identified and known to be non-toxic.
- If the mushroom variety is known to resist colonization by toxic molds.
- When mycelium or base of the mushroom shows no mold penetration.
However, remember consuming any wild mushroom carries some degree of risk. Proper identification is crucial, and if in doubt, it is always safer to avoid eating moldy mushrooms found in the wild.
What Does White Mold on Wild Mushrooms Look Like?
Benign white mold on wild mushrooms can appear as:
- Sparse small white spots
- Powdery white spore deposits on caps
- White fuzzy patches or threads localized to small areas
Conversely, toxic molds like Fusarium tend to show dense cottony white growth penetrating into the mushroom tissue, signaling the mushroom should not be eaten.
Can You Make a Moldy Mushroom Safe to Eat by Cooking It?
Cooking a mushroom with white mold does not make it safe to eat. High heat from cooking may kill the mold fungus, but has little effect on mycotoxins that may be present in the mushroom tissue. These mold byproducts are heat stable and can survive normal cooking temperatures.
For example, studies show the mushroom toxin agaritine breaks down significantly when boiled, but other toxins like gyromitrin from the deadly poisonous mushroom Gyromitra esculenta remain active even after boiling or drying.
Cooking also cannot remove the long root-like filaments mold has embedded into the mushroom flesh. For safety, assume anything with more than a tiny patch of surface mold should be thrown away regardless of cooking.
Methods Ineffective for Making Moldy Mushrooms Edible
Here are some common methods that do NOT make moldy mushrooms safe to eat:
- Washing – does not remove mold roots or toxins
- Peeling – mold likely penetrates deeper than the skin
- Boiling, steaming, frying – most mycotoxins withstand cooking temperatures
- Canning or freezing – heat-stable toxins remain active
The only reliable approach is to discard and not consume mushrooms that are moldy. Simply removing the visible mold is not enough to make them safe for eating.
How Can White Mold Growth on Mushrooms be Prevented?
Proper storage and handling helps prevent mold growth from developing on mushrooms in the first place.
For Store-Bought Mushrooms
- Keep unwashed mushrooms refrigerated in paper or cloth bags, not sealed plastic
- Wash just before use, don’t leave moist
- Watch for bruises, damage, or slimy spots signaling spoilage
- Use within several days of purchase for best quality
For Wild Mushrooms
- Gather young, freshly emerged mushrooms, avoid old specimens
- Clean gently with a soft brush, avoid immersing in water
- Dehydrate thoroughly if drying for storage
- When rehydrating, use a 0.5% salt solution and refrigerate
- Consume reconstituted mushrooms within several days
Following good handling and storage methods helps mushrooms resist mold growth and last longer in top condition.
Conclusion
Eating mushrooms with white mold is unsafe in most cases. For store-bought mushrooms, white mold signifies food spoilage and possible toxicity, so they should be discarded. With wild mushrooms, eating them with white mold requires confident identification of both the mushroom type and mold species to determine edibility. In either case, it is wise to err on the side of caution if mold is present on mushrooms. Cooking cannot detoxify moldy mushrooms or remove mold filaments. Preventing mold growth by proper handling and storage is key to avoiding possible issues with white-molded mushrooms.
Key Points
- Do not eat store-bought mushrooms with any white mold, as it indicates spoilage.
- Only eat wild mushrooms with white mold if you can identify the mushroom and mold species and confirm the mold is safe.
- Cooking does not detoxify toxic molds or remove penetrating mold filaments.
- Discarding moldy mushrooms is the only safe option unless mold is positively identified as benign.
